The number of value added services that can be delivered in circuit switched networks, such as fixed and mobile networks, is increasing fastly as a result of, amongst others, the booming mobile telecommunications market. Developments such as the rolling out of UMTS over the past years enable the use of for example mobile phones for a large number of services such as regular voice calls, mobile broadband internet services, short messaging service (SMS), multimedia messaging service (MMS), but also numerous different charging schemes, security related services such as number dependent blocking of telephone calls, etc.
The services available are often dependent on the terminal or communication device used for accessing the telecommunication network. As an example, one may consider a telecommunication device which is restricted in use on the network, in that only telephone numbers in a specific area may be called using that communication device. Another example is the availability of multimedia service capabilities of a communication device, enabling the user thereof e.g. to receive MMS-messages.
Call forwarding is another of these value added services, which is widely used in circuit switched telecommunication networks. If for example party A is trying to reach party B, while party B is not able to pick up the phone due to e.g. absence, party B may have instructed the network to forward all incoming calls on his home telephone number to the phone of a friend, party C, where B can be temporarily reached. Although this service has increased the reachability of users of a telecommunication network a great deal, services such as call forwarding also provide new problems and challenges to overcome within the telecommunications industry.
A disadvantage of call forwarding is that party A may not aware of the forwarding of the call to party C, and of the service level that can be provided to party C and/or the terminal used by party C. In general, party A may not know that he is connected to party C, and as a result or in addition, may not be aware of the value added services available to party C.
It is noted that call forwarding is triggered by the switching device to which party B (i.e. his terminal unit) is connected on the circuit switched telecommunication network. Upon receiving an incoming call for party B, the mobile switching centre (MSC) (being a gateway MSC or visiting MSC) to which party B is connected, consults the service control point (SCP) or the home location register (HLR) with which this is associated and finds a call forwarding to party C. It thereupon forwards the call to an MSC (or local exchange in a wireline network) to which party C is connected, for delivering the call.
When the call is answered, the integrated services digital network (ISDN) user part (ISUP) or bearer independent call control (BICC) may provide an indication of the connected number (party C) to party A's terminal, however this will merely provide the connected number to party A. This will not be sufficient for A to determine the service level available to C, nor does the sending of this information provide a possibility to invoke further services.